The present invention relates to a candle having a first region containing a material that is opaque at room temperature and a second region that is transparent or substantially transparent at room temperature. More particularly, the material comprising each region of the candle is selected and processed to minimize the diffusion of the respective regions into each other and to maintain the original appearance of the candle for as long as possible while the candle bums. A process for making such a candle is also provided.
Candles are used as sources of light and often as attractive ornaments. Candles may be made from solid wax compositions. Opaque candles are typically made from paraffin or stearic acid. Paraffin is advantageous because of its lower cost; but, stearic acid has better burning characteristics. To cost optimize the properties of a candle, a mixture of paraffin and stearic acid is often used as disclosed, for example, in Thompson et al., U.S. Pat. No. 2,638,411 or Beardmore et al., U.S. Pat. No. 4,118,203.
The performance properties of a candle may be improved using various techniques. For example, Luken, Jr. et al., U.S. Pat. No. 4,759,709 disclose how to improve wax candles by over-dipping the candle in a blend of specific paraffins, fatty acids, and alpha-alkyl branched carboxylic acids to minimize streaks and color patches.
Making clear or transparent candles is also known. For example, Miller et al., U.S. Pat. No. 3,645,705 disclose a light, clear mineral oil and/or a natural oil as a gel base, a polyamide resin as a gelling agent, and a C8-C10 or C12 primary alcohol, which enhances the burning characteristics of the oil-polyamide gel system. Gunderman et al., U.S. Pat. No. 3,819,342 disclose a transparent candle composition containing a thermoplastic polyamide resin and a flammable solvent capable of solubilizing the resin at a temperature below about 100xc2x0 C. to provide a transparent gel-type structure.
Elsamaloty, U.S. Pat. No. 5,578,089 discloses a clear candle containing a two-phase system, which includes an xe2x80x9coilxe2x80x9d phase and a xe2x80x9cblock co-polymerxe2x80x9d phase. To achieve desirable properties for a stable, safe, and attractive clear candle, the gel consistency may be controlled by varying the amount, ratio, and types of the copolymers, including di-block and tri-block copolymers.
Spaulding et al., U.S. Pat. No. 6,054,517 disclose a composition for a solid transparent candle containing one or more polyamide resins present in a total amount of about 60-80% by weight of the composition, one or more solubilizers, and one or more emulsifiers. Berger et al., U.S. Pat. No. 6,111,055 disclose ester-terminated dimer acid-based polyamides that may be blended with a solvent to form a gel. The solvent may be flammable, and a wick may be added to the resulting gel to form a candle.
Because candles are also used as decorative ornaments, processes for enhancing their appearance have been sought. For example, Campbell et al., U.S. Pat. No. 3,771,445 disclose the use of screen-printing to provide decorative candles. Bell et al., U.S. Design Pat. No. D 407,164 disclose candles with a pearl-like appearance. Freeman et al., U.S. Pat. No. 6,068,472 disclose a method of making candles that are decorative. Such candles have an inner chamber and an outer layer. Fawcett, U.S. Pat. No. 5,927,964 discloses candles with decorative metal particles. Tanikawa, U.S. Design Pat. No. D 246,010 discloses another ornamental design for a candle. And, Hsu, U.S. Design Pat. No. D 397,459 discloses a candle with a spiral core.
Candles that have multiple colored layers to provide a decorative effect are also known For example, Ficke et al., U.S. Pat. No. 6,129,771 disclose the use of multi-layer gel candles with different colorants. The respective layers, however, are made from the same gel material, and may be differentiated with e.g., different colors and different perfumes. Such candles are disadvantageous because the layers tend to run together during storage, which may require special barrier layers to prevent.
Karp, U.S. Pat. No. 5,395,233 (xe2x80x9c""233 patentxe2x80x9d) disclose a candle with an opaque core and a shell of transparent wax which leaves a gap between the core and the outer shell. This gap is filled with a mixture of the transparent wax and potpourri materials that camouflage any migration of the opaque layer into the outer transparent layer. The ""233 patent also discloses that when the candle is lit, the inner wax core is burnt without melting the potpourri layer and outer transparent layer, thus maintaining the integrity and decorative ambiance of the candle provided by the visible potpourri.
In sum, the patents summarized above do not disclose how to manufacture a stable candle composed of adjacent opaque and transparent layers, whereby both layers are used as a fuel source, and migration of the opaque layer into the transparent layer is minimized.
Accordingly, it would be advantageous to provide a candle that is easy to make, and that has adjacent regions that are transparent (or substantially transparent) and opaque, which regions are stable with respect to migration, and are both used as fuel. Such a candle provides both a decorative effect and a cost effective, stable candle. It would also be advantageous to provide a process for making such a candle.
One embodiment of the invention is a candle that includes a container having a bottom and a side wall defining a cavity and a top rim delimited by the side wall. A first region containing a material that is opaque at room temperature is disposed within the cavity of the container. A second region containing a polymer-oil blend that is substantially transparent at room temperature is disposed within the cavity of the container and is adjacent to the first region. A wick is disposed within the container, which passes through both the first and second regions.
Another embodiment of the invention is a process for producing a candle. This process includes (a) providing a substantially transparent container having a bottom and a side wall defining a cavity and a top rim delimited by the side wall; (b) dispersing into the cavity of the container a flowable material selected from the group consisting of a wax, a fatty acid, or a combination thereof that forms a solid, opaque layer at room temperature; (c) allowing the flowable material to cool to below about 35xc2x0 C.; (d) dispersing into the cavity of the container a flowable material containing a polymer-oil blend that forms a solid, substantially transparent layer at room temperature; and (e) positioning a wick within the cavity of the container wherein the wick is in contact with both the opaque and substantially transparent layers.